pg_index

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pg_index

The pg_index system catalog table contains part of the information about
indexes. The rest is mostly in pg_class.

Table 1. pg_catalog.pg_index

column

type

references

description

indexrelid

oid

pg_class.oid

The OID of the pg_class entry for this index.

indrelid

oid

pg_class.oid

The OID of the pg_class entry for the table this index is
for.

indnatts

int2

The number of columns in the index (duplicates
pg_class.relnatts).

indisunique

boolean

If true, this is a unique index.

indisprimary

boolean

If true, this index represents the primary key of the table.
(indisunique should always be true when this is true.)

indisclustered

boolean

If true, the table was last clustered on this index via the
CLUSTER command.

indisvalid

boolean

If true, the index is currently valid for queries. False means the
index is possibly incomplete: it must still be modified by
INSERT/UPDATE operations, but it cannot safely be
used for queries.

indkey

int2vector

pg_attribute.attnum

This is an array of indnatts values that indicate which table
columns this index indexes. For example a value of 1 3 would mean that the first and
the third table columns make up the index key. A zero in this array indicates that the
corresponding index attribute is an expression over the table columns, rather than a
simple column reference.

indclass

oidvector

pg_opclass.oid

For each column in the index key this contains the OID of the
operator class to use.

indexprs

text

Expression trees (in nodeToString()
representation) for index attributes that are not simple column references. This is a
list with one element for each zero entry in indkey. NULL if all index attributes are
simple references.